


The Case of the Poison Mocha

by CatieBrie



Category: Sherlock (TV)
Genre: Case Fic, Comedy, Crack, Gen, Gen Fic, I didn't know it was possible, and a very annoyed Sherlock, enjoy John on a caffeine high, omg I actually wrote something funny and gen, this is meant to be fun and pointless and a break from my usual ultra-dark fic
Language: English
Status: Completed
Published: 2015-02-14
Updated: 2015-02-14
Packaged: 2018-03-12 10:13:00
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,048
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3352766
Author URL: https://archiveofourown.org/users/CatieBrie/pseuds/CatieBrie
Summary: <blockquote class="userstuff">
              <p>Or Sherlock versus Starbucks and a caffeine high John Watson.</p>
            </blockquote>





	The Case of the Poison Mocha

**Author's Note:**

> Okay, so this is delightful nonsense. It was meant to be a fill for this [prompt](http://sherlockbbc-fic.livejournal.com/22393.html?page=66#comments) on the Sherlock kink/prompt meme, but I took forever to write it. 
> 
> This is for you, lovely readers! Happy Valentines.
> 
> This is based on the comments/mini fills on the OPs original prompt
> 
> ALSO! The epi-pen usage in this fic is inaccurate and not to be taken as responsible medical practice!

Two people had died at the Starbucks three blocks down from New Scotland Yard; pretty men with pendulum hips and topiary-sculpted hair.  Anaphylactic shock, forensics said holding up charts to prove their point.  Lestrade thought murder, and rightly so, but Sherlock didn’t want to take the case.  It ranked a shaky three, a two if you took out the pretty men, and Sherlock wanted nothing more than a seven at the moment.  

“We’ll do it,” John said before Sherlock could open his mouth and state dramatically what he thought of the case and the Met’s intelligence.

“We will not!”

“Free coffee, Sherlock.”  John turned something of a manic grin on Lestrade and Lestrade shrugged.  

“Why not? I’m gunna need you two to stake out the Starbucks and not having a drink while you’re there would look suspicious.”

“Pointless!” Sherlock snapped.  “It’s that stupid kid with the too long hair working the register.  Jealous type. Did you check his Facebook?  Maybe he’s a spurned lover.”

“If I can’t have you, no one else can!” John exclaimed before giggling that odd, high pitched giggle he had that didn’t fit with the soldier or doctor persona he tried to affect during everyday life. Lestrade and Sherlock gaped at him and he laughed harder.  “I’m sorry, it’s been awhile since I’ve slept. Do go on.”  

Lestrade waited until John calmed down before continuing.  “Well, we need evidence. It looks like they really did die of anaphylactic shock.  If it’s the kid, he’d have to’ve planned exactly how he’d kill the two. Know their schedule, know their allergies.  Spurned lover seems most likely.”

“Case solved then,”  Sherlock said, nose in the air.  “Check his Facebook and you’ll be golden.”

“He doesn’t have one.” Lestrade said.  “Besides, could be any of the baristas, if we’re going that route, not just the boy.”

“It’s the boy.”  

“Then prove it.”  Sherlock glared, but Lestrade had used the magic words.

\--

They would have started immediately but Sherlock insisted John get a nap in after his friend had started on about the Grand Epic of the Spurned Barista during the cab ride home. The story had started on an upward climactic slope before John burst into giggles, once again, and didn’t stop until they arrived at Baker Street.  

When John woke he was quite surly and Sherlock almost wished he had the punch-drunk John back as they left for the Starbucks they would be staking out for however long.  

“Twenty minutes is not a proper nap,” John snapped when Sherlock pointed out how unreasonably grumpy John was being.  

“Ten to twenty minutes is the optimal time for a—”

“Oh, don’t you start spouting science at me like I’m an idiot, I know about sleep cycles and I also know that after being up forty-eight hours straight that twenty minutes is not enough.”  John pushed the glass door open, coffee warm air spilling out and wrapping them both in comfort from the bleary cold February day.  John didn’t hold the door for Sherlock, muttering under his breath as he headed for the line: “Optimal my arse.”

Sherlock followed, definitely not sulking as he took his place in line beside John. He ordered and paid before John, stating “Sherlock,” when prompted for his name and then stomped off to claim a table.  John could handle the rest. He’d be useless for much else until he consumed some form of caffeine anyways.

In the meantime, Sherlock was dead set on the long-haired and angry cashier/barista as his suspect.  He did his best to search out some form of social media the kid had attached his name to while he waited on John to join him.

Sherlock looked up from his laptop as John finally approached their little table, the doctor’s face red with amusement.  He held two paper cups in hand, and that was all Sherlock needed to know.  

“Sherman.”  John giggled as he sat down, handing the smaller cup to Sherlock.  “Mine’s just missing the h, not so bad, but Sherman?  You don’t even look like a Sherman.”

Sherlock ignored the jibe and turned his attention back to the blog he had opened on his screen.  It was a garish thing, black and white with red text just the right shade to blind the average eye.  He sneered.  

“Does that happen a lot, them screwing up your name?”  John said after a few minutes of silence had passed.  He’d already torn the cardboard sleeve to pieces from around his cup, foot tapping against the ground, eyes shifting to and from the bar.  He was bored but at least in something of a better mood.

“Yes.”  Sherlock pulled the screen of his laptop down so that he could better glare at his friend.  “You’re supposed to be watching the cashier, John.”

“I am, and it’s all rather dull,” John said and Sherlock noticed that the pulse in his throat had jumped slightly, his pupils just a bit larger.  On any other day Sherlock would have deduced John was aroused, but he had no other tells.  No, this time John was hopped up on caffeine.   He was not handling the fidgety mess it made him very well at all. “He’s just leaning against the bar, like he has been for the past ten minutes.  Even when customers come up, he leans against the bar until the pretty blonde one nudges him into action—he was rather rude to us when we ordered you know.”  

“Was he now?”  Sherlock watched the way John tilted the rest of his drink into his mouth, swallowed and then inhaled for an explanation.

“Oh yes, very rude indeed.  Didn’t look up when you ordered, kept about half your change and I’m pretty sure he gave you soy milk, isn’t that what the little s in the milk box means?  You don’t even take milk. How did you not notice?”

Sherlock stared at his untouched coffee and then back at John, not sure if he should be impressed by his deductive skills or irritated that John hadn’t called the cashier out for shortchanging him.  “I got your money back when I ordered, but I think I’m going to keep it as repayment for my jumper you destroyed last week.”

“It was for an experiment, John.”

“You could have bought a jumper to experiment on!” John exclaimed, waving a hand emphatically and knocking over his cup with a hollow thump, empty cardboard rolling across the table to rest against Sherlock’s computer.  Sherlock looked down at the list of boxes and read instructions for three shots of espresso.   _Three shots?!_  “It was my favorite.”

“The oatmeal one?”  Sherlock asked, tearing his gaze away from the drink instructions to stare down John.  “You’ve worn it once! And it was hideous, I was doing you a favor.”

“Destroying someone’s clothes with acid is not a favor.”

“Freed up your wardrobe for something attractive,” Sherlock snorted, turning his attention back to the blog he had pulled up on his screen.  He was reasonably sure the kid in the icon was the same one working the register, but his hair covered too much of his face.

“Oi!” John leaned into Sherlock’s personal space, closing the laptop with one hand as he used the other to balance.  “Are you calling me unattractive?”

“John we’re here on a case, pay attention!”

“Are you?”

“No! I’m calling your fashion choices unattractive, now pay attention.” John sat back, folding his arms over his chest as he leaned back.

“I like my jumpers.”

“I’m sure, but that’s really not the point.”  Sherlock was getting a headache.  He reached for his own coffee and took a sip, grimacing at the taste.  He really hated any kind of milk in his drink but he was going to need the energy to deal with John and a case.

“What’s the point, then?”

Sherlock rolled his eyes heavenward and then looked at John who was, quite frankly, failing miserably at sitting still.

“The point is irrelevant.  We have a case and if you really want to discuss my thoughts on your jumpers, we can do so at home.”

“I want to now, it’s far more interesting than this stupid case.”

“John, you volunteered us!”

“I just wanted the coffee.”

“I hate you.”  John just smiled, wide and amused and completely unaffected by Sherlock’s quickly declining good humor.

“Oh look, the kid’s gone.”  John said after a moment, completely unconcerned and why was Sherlock the only one who seemed to care about this stupid, godforsaken case when _he hadn’t even wanted to do it in the first place?_

“John, you were supposed to be watching!”

“Can’t watch and argue over my fashion choices at the same time, now can I?”

“One of those baristas, very likely the one that has left, is a murderer and you’re concerned with what I think of your jumpers?”

“You can’t expect a man to take an insult lying down, now can you?”  John grinned.  “Besides, the pretty blonde one gave me his schedule for the next week.”

“And why did she do that?”

“I told her you thought he was cute but didn’t have enough courage to ask him out yet.

Sherlock was going to kill him, god help his soul, he was.

\--

They came back the next day and Sherlock had to wonder why they were even trying.  This case was stupid, John was being more obnoxious than usual (wasn’t he supposed to be the sane one?  Isn’t that what everyone said when they saw them together?) and the more he thought about it, the more he wondered why NSY couldn’t handle this on their own. He was surrounded by idiots.

He ordered and gathered his cup before his name could be called out.  He didn’t trust them not to muck it up.

Good thing too. _Shercock, really_?  Sherlock thought horrified after he grabbed his coffee from the counter, checking it for milk (soy or otherwise) before walking away.  The kid didn’t try to shortchange him this time, probably because John had postured behind Sherlock, back straight and spine soldier-stiff.  Or maybe the ‘pretty-one’ had told him about Sherlock’s supposed crush and he was being nice—Sherlock looked at the name again, and groaned.  Definitely not being nice.

"The kid's an idiot," John said as they sat at the same table as the day before.  Sherlock raised an eyebrow but was otherwise too absorbed in the frankly heinous name the cashier had scribbled across his cup. _Shercock, honestly!_

"Who even spells John J-a-w-n?" He held the cup out for Sherlock to see and sure enough _Jawn_ was scribbled halfheartedly under the plastic lid.  Still, it was better than Shercock.

"Did they get yours right, at least?" John cocked his head to the side in question, eyes searching the cup for the sharpied name. Sherlock tried to cover it with spread fingers, making to take a sip, but John was the literal embodiment of tenacious and before Sherlock could move, the cup was gone from his fingers and John was examining the scrawled monstrosity.

“You know what,” John said, voiced cracking over the words in his attempt not to laugh.  “I’ll take Jawn, Jawn is a good name, an honest name.”

He handed the cup back to Sherlock, face smooth and expressionless for all of five seconds before he started giggling that oddly endearing high-pitched giggle.  Well, it was usually endearing, but right now Sherlock just wanted to throw something to make him shut up.  “Shercock, really?  Sounds like a porn-star name, my god!”

“Watch the damn cashier, _Jawn_ ,” Sherlock snapped as he pushed his laptop open and started checking up on the latest blog updates.  

\--

“Shirley!?” Sherlock squawked. That was it, he’d had it.  This stupid case and his stupid flatmate were going to be the death of him.  “Shirley? Really? Are the lot of you daft?  How do you get Shirley from Sherlock?”

“I’m sorry, he’s a bit high strung.”  John was saying as he pulled Sherlock away from the counter and back to his chair.  “He’s had a long week.”

“A long week?”  Sherlock rounded on John.  “And whose fault is that?”

“Mine.”  John smiled, completely unperturbed and unmoved by Sherlock’s plight.  Damn it, the doctor was supposed to be on his side.  “Now how about we sit down and enjoy our coffee, hmm?”

The baristas just stared as John continued to tug Sherlock to what had become ‘their table.’

Sherlock sulked for the rest of the day.

\--

“There’s no case.”  Sherlock claimed as they walked into the Starbucks for a fourth time.  “No case at all.  There can’t be—this is all too—”  Sherlock waved his hands around to encompass the sheer ridiculousness of their situation.  John just nodded along, very obviously not listening at all. When all this was over Sherlock was going to burn every last one of John’s jumpers as revenge for this stupid, pointless—

“What can I get for you today?”  It was the long haired boy at the cashier again.  He was smiling, or trying to.  Sherlock sneered.

“Grande cafe mocha,” he snapped. “Extra shot of espresso.  Actually, make it a vente and add another shot—if I’m going to have to work on this godforsaken thing, I might as well order something expensive. Soy is extra yes? Yes. Do that as well.”

The kid had stopped smiling, face having slipped back into a petulant scowl.  “Name?”

 _You know my name by now you little snot_ , Sherlock though uncharitably. Well, if Sherlock hadn't worked so far maybe something else would. “Scott.”

He paid and went over to their table, spine stiff with irritation.

“You’re going to hate your drink,”  John said when he joined him at the table.  

"It'll be sweet, I'll be fine."

"No, you pissed him off—I bet you he burns the espresso beans and uses skim just to spite you."

Sherlock snorted. "Whatever you say."

John was right.  When he finally got his coffee the drink itself was like warm charcoal, the strong flavor of carbon and watery milk taking over his tongue. And the name. He just didn't understand how they could screw up Scott.

"Oh that's perfect!" John said when he read the name.

"Perfect? It a bastardization of a—why are you staring at me like that?"

John looked horrified.

"You don't know Star Trek?"

“Is this another one of your stupid shows?”

“Doctor Who is not—you know what, never mind.  Talking to you about pop-culture is pointless.” John slumped back in his seat, pouting in the most I-am-not-pouting fashion Sherlock had ever witnessed.

Sherlock scoffed.  “Just watch the cashier.”

It wasn’t until Sherlock had finished about half his drink that he noticed a tightening in his throat, a phantom grip that itched like nettle.  His eyes went wide and when he tried to speak it was a garbled hiss.

“Sherlock?”  John quickly dropped his pout and sat straight in his chair. “Shit.”

Sherlock could feel his lips beginning to balloon up and panic had settled into his bones and _why was John so calm_?

“Hold on, I know I have something for that on me,”  John stood and patted down the pockets of his jacket.  “Ah-hah!”

Sherlock tried to scramble away, but John had already rounded the table and grasped the meat of his thigh.

“This’ll hurt.” John said before jabbing the thick— _demonic!_ Sherlock thought wildly—needle of an epi-pen into his leg.

Sherlock felt his heart rate skyrocket; his breathing fast and hollow but at least unheeded by a swollen throat.  He swallowed, dropping his head between his knees as he waited for the effects to wear off.  In his periphery he saw the doors to the Starbucks burst open; he heard John talking him through the sudden wave of adrenaline soaking into his system.

When Sherlock’s heart rate settled back to normal he was surprised to see Lestrade and several beat cops crowded into the tiny cafe, the stringy haired kid in cuffs.

Sherlock stared at the activity around him.  “What just happened?”

John waved the epi-pen in hand, eyes huge with triumph.  “I solved a case.”

“What?”

“I solved a case.”

“John. _Elaborate_.” Sherlock felt light headed and agitated.  John capped the epi-pen and grinned.  

“Well, there’s been a rash of kids suffering unprecedented allergic reactions at the clinic.  A few cases even resulted in anaphylactic shock.  Most kids were okay, they came by to get allergy tests and—funny thing, they still didn’t show any signs of actually being allergic to anything.”

Sherlock saw where this was going, and if he was right he very well might kill John.

“So we did some blood tests.  Each kid tested positive for an unknown substance—they’re still trying to figure out all the components but basically it forces the body to experience an allergic reaction ranging from irritating to fatal.”

“Uh-huh.”

John continued, unaware he now faced mortal peril. “So after Greg briefed us on the case, I directed him towards a friend who had done most of the blood work and turns out the same substance showing up in these kids was also in the toxicology report on the two Starbucks victims.”

“So you had it solved before we even started?”

“Well, I didn’t have a suspect! So I suppose I solved half the case.”

“We didn’t need to even be here.”

“Nah, but the free coffee was nice.”

“I’m going to kill you.”  Sherlock smiled and John blanched.

“What?”

“You heard me.”

“Errm, well then, I better...run?"

“I’ll give you a head start.”

“Are you serious?”

“Five.”

“It’s not like you haven’t dragged me around on useless cases—”

“Four.”

“Oh come on!”

“Three.”

John got up just as Lestrade approached.  “Great job, John.  We’ve got all the evidence we need to book this guy—”

“Two.”  John grabbed his coat and smiled apologetically at Lestrade.

“Uh, thanks.  I’ll talk to you later, something’s come up and I er—yeah.”  John ran.

“What was that about?”

Sherlock stood with enough force to knock his chair back.  “One.”

And off he ran, long legs taking him out the door faster than Lestrade could move to stop him.  

  
“YOU DESTROYED MY JUMPER!!” Wafted in on the coffee warm air and then the door slammed shut behind them.

**Author's Note:**

> Come find me on [tumblr](http://catie-brie.tumblr.com/) where I love to answer questions, comments, chats or just have you as a friendly stalker. It's also where I periodically post about fanfic I am working on.
> 
>  
> 
> (Side note: I have talked to a lot of Starbucks baristas about this name meme that seems so popular and while amusing to us, this often is a point of irritation and stress for the barista. As a dear friend said: "I’m sorry you would feel pressured giving your name, but understand there’s pressure on the other end as well. While you’ve been spelling your name the same way for two decades, we have not been: Kaley, Kalie, Kaylee, Kaily, Kayleigh, Kaleigh, Kayley, and everything else in between comes through our store, and we can’t just guess at which one will be correct. Adrienne classically, or the more androgynous Adrian? Katy with a C, K, ie, ee, or y? Sarah with an h or nah? Mark? Is that a C or K? John, is that short for Jonathan (no h), or is it just John? I could go on and on: names in English are simply not that easy."
> 
> Side note 2: As has been pointed out to me by Father_Time, this is an inaccurate portrayal of epi-pen usage and in reality Sherlock would still have had to go to the hospital afterwards, especially after consuming the allergen.)


End file.
